You work as a network Exchange administrator at Company.com.The Company.com network currently consists of a single Active Directory forest containing a single domain named Company.com.The Company.com organization makes use of Microsoft Exchange Server 2010 as their messaging solution.you are responsible for managing three mailbox servers named - ex01， -ex02 and -ex03.during the course of the week you receive an instruction from management to configure a journaling mailbox on ex03 as well as to configure journaling on various mailboxes in -ex01 and -ex02.to ensure productivity you need to make sure that journaling will continue to happen in the event that -ex03 failing.What should you do？（）

A. Your best option would be to create a retention tag.Thereafter the tag needs to be assigned to the new retention policy.
B. Your best option would be to have the shadow redundancy settings confnfigured in the organization.
C. your best option would be to have an alternate journaling mailbox configured on -ex02.
D. Your best option would be to have a second e-mail address configured for the journaling mailbox.